Recent advances in the field of minimally invasive cardiac surgery have included the development of aortic catheters and methods for inducing cardiac arrest without the necessity of opening the patient's chest with a sternotomy or other major thoracotomy. For example, U.S. Pat. No. RE 35,352 to Peters describes a single balloon catheter for occluding a patient's ascending aorta and a method for inducing cardioplegic arrest. A perfusion lumen or contralateral arterial cannula is provided for supplying oxygenated blood during cardiopulmonary bypass. U.S. Pat. No. 5,584,803 to Stevens et al. describes a single balloon catheter for inducing cardioplegic arrest and a system for providing cardiopulmonary support during closed chest cardiac surgery. A coaxial arterial cannula is provided for supplying oxygenated blood during cardiopulmonary bypass. The occlusion balloon of these catheters must be very carefully placed in the ascending aorta between the coronary arteries and the brachiocephalic artery, therefore the position of the catheter must be continuously monitored to avoid complications.
In clinical use, in patients with incompetent or regurgitant aortic valves, antegrade infusion of cardioplegia by aortic root injection is contraindicated because the pressure generated by infusion of cardioplegia overcomes the reduced competence of the valve, causing cardioplegia to enter the ventricle rather than entering the coronary arteries. In some cases the left ventricle may become distended. In patients with incompetent or regurgitant aortic valves, it is recommended that cardioplegia be administered by direct coronary cannulation or by retrograde perfusion through the coronary sinus. Direct coronary cannulation can be difficult and can dislodge plaques from ostial lesions in the coronary arteries. Retrograde perfusion of cardioplegia through the venous system has been used successfully, however, there is debate as to the effectiveness of this procedure, and correct placement of the catheters can be difficult. Furthermore, even in patients with normal aortic valves, pressures generated during surgery may cause the valve to become temporarily incompetent, leading to problems similar to those discussed above.
Another difficulty encountered with prior art aortic catheters is the tendency of the single balloon catheters to migrate or drift in the direction of the pressure gradient within the aorta. Specifically, during infusion of cardioplegia, the balloon catheter will tend to drift downstream away from the heart and toward the aortic arch and, while the cardiopulmonary bypass pump is on during the procedure and after completion of infusion of cardioplegia, the balloon catheter will tend to drift upstream in the opposite direction toward the heart into the aortic root. This migration can be problematic if the balloon drifts downstream far enough to occlude the brachiocephalic artery, or upstream enough to occlude the coronary arteries, or to pass through the aortic valve into the ventricle.
What is needed is a peripheral or central access catheter configuration that maintains the competence of weakened aortic valves, and does not challenge the competence of healthy aortic valves, during infusion of cardioplegia, and is more resistant than prior apparatus to migration due to pressure gradients within the patient's aorta.
The following patents are hereby incorporated herein in their entirety: U.S. Pat. Nos. 5,383,854, 5,308,320, 5,820,593 and 5,879,316 by Safar et al.; U.S. patent applications Ser. No. 08/909,293 filed Aug. 11, 1997, Ser. No. 08/909,380 filed Aug. 11, 1997 and Ser. No. 09/152,589 filed Sep. 11, 1998, by Safar et al.; U.S. Pat. No. 5,738,649 by John A. Macoviak; U.S. Pat. Nos. 5,827,237 and 5,833,671 by John A. Macoviak and Michael Ross; and U.S. patent application Ser. No. 08/665,635, filed Jun. 17, 1996, by John A. Macoviak and Michael Ross; U.S. patent application 09/205,753, filed Dec. 8, 1997, by Bresnahan et al.